Remotely/Shared/Extensions/StreamExtensions.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Remotely.Shared.Extensions;

public static class StreamExtensions
{
    public static async Task CopyToAsync(this Stream source, Stream destination, Action<int> bytesReadCallback)
    {
        var buffer = new byte[64_000];
        var totalRead = 0;

        int bytesRead;

        while ((bytesRead = await source.ReadAsync(buffer)) != 0)
        {
            await destination.WriteAsync(buffer.AsMemory(0, bytesRead));
            totalRead += bytesRead;
            bytesReadCallback.Invoke(totalRead);
        }
    }
}